Endoscopic suture cinch system

BACKGROUND OF THE INVENTION

p-00021. Field of the Invention

p-0003The present invention relates to a device that can be inserted into a body through a natural orifice with an endoscope or other steerable guide member. The present invention may be used in conjunction with a suturing instrument to secure an applied suture to the tissue of a mammal, whether human or not, and whether or not alive.

p-00042. State of the Art

p-0005Natural Orifice Translumenal Endoscopic Surgery (NOTES) involves passing surgical instruments in association with an endoscopic camera through a natural orifice, such as the mouth, vagina, or anus, to a desired organ. By avoiding major incisions through the skin, muscle, and nerves of the abdomen, patients may experience a quicker recovery with less pain and scarring while further reducing the post-operative risk of surgery.

p-0006In co-owned US Pub. No. 20090312775A1, an endoscopic suturing device suitable for use in a NOTES procedure is described. The device has a structure with a sufficiently small distal profile for delivery through a natural orifice, while providing a needle movable on an arm through a large opening and closing angle and which produces a large force upon the needle for piercing tissue to perform a surgical operation such as tissue approximation and suturing. A length of suture is permanently attached to the needle and forms stitches about tissue engaged at the distal end of the device as the needle is moved through the tissue and the distal end of the device is moved relative to the tissue. After one or more stitches have been formed in the tissue, the needle is released from the device and the free end of the suture is secured relative to the tissue. In accord with one manner of securing the free end of the suture, portions of the suture may be tied together about the tissue. In accord with another manner of securing the suture, a cinch element is advanced over the suture and cinches the tissue between the needle on one side of the tissue and the cinch on the other side of the tissue. The suture is then severed.

p-0007In addition to the cinch and cinch-applying instrument described in the above-referenced publication, other cinch instruments and deployable cinches are known. For example, referring to prior art <figref idrefs="DRAWINGS">FIG. 1</figref>, also known is a cinch applicator <b>10</b> for use in deploying the two parts <b>12</b>, <b>14</b> of a cinch onto suture <b>16</b> in a NOTES procedure. The applicator <b>10</b> includes an elongate flexible tubular member <b>18</b>, a hypotube <b>20</b> fixed to the distal end <b>22</b> of the flexible tubular member <b>18</b>, a flexible shaft <b>24</b> extending through the tubular member <b>18</b> and the hypotube <b>20</b>, and a proximal handle (not shown) for moving the shaft <b>24</b> longitudinally relative to the tubular member <b>18</b>. The hypotube <b>20</b> defines a distal housing <b>26</b> and a proximal lateral window <b>28</b>. A slidable plunger <b>30</b> provided with a guillotine <b>32</b> is provided within the hypotube <b>20</b>, with the guillotine <b>32</b> fully proximal of the housing <b>26</b> and distal of the lateral window <b>28</b>.

p-0008The two-part cinch includes a collar <b>12</b> and a plug <b>14</b> engageable within the collar. The collar <b>12</b> has a cylindrical outer shape that is retained in the distal housing <b>26</b> of the hypotube <b>20</b> with a simple dimpling mating structure. The collar <b>12</b> also includes a proximal inner lip <b>33</b>, and an outer lip <b>34</b> seating at the distal end of the hypotube <b>20</b> and having a flat distal facing end <b>35</b>. The plug <b>14</b> of the cinch is attached to the distal end of the flexible shaft <b>24</b>. The plug <b>14</b> has an enlarged distal flange <b>36</b> corresponding in size and shape to the outer lip <b>34</b> on the collar <b>12</b>. The plug <b>14</b> has an elongate tubular body <b>38</b> defining a throughbore <b>40</b> in which the flexible shaft <b>24</b> extends, and a proximal circumferential exterior groove <b>42</b>. A distal portion of the shaft <b>24</b> has a bend <b>44</b> to facilitate retention within the throughbore <b>40</b>. The distal end of the shaft <b>24</b> has a rounded bead <b>46</b> that sits at the flange <b>36</b> of the plug. The bend <b>44</b> and the bead <b>46</b> trap the flexible shaft relative to the plug.

p-0009In operation, from outside the patient, the proximal end of the suture <b>16</b> is thread through the collar <b>12</b> and hypotube <b>20</b> and out of the lateral window <b>28</b>. Then the applicator <b>10</b> is advanced through an endoscope so that the elements of the cinch are provided adjacent the stitched tissue. When the handle is operated, the shaft <b>24</b> is retracted to draw the plug <b>14</b> into an interference fit within the collar <b>12</b>, with the inner lip <b>33</b> of the collar positively engaging the outer groove <b>42</b> on the plug. The suture <b>16</b> is captured between the outer surface of the plug <b>14</b> and the inner surface of the collar <b>12</b> so that the cinch is secured to the suture. Upon further retraction of the shaft <b>24</b>, the shaft is pulled such that the bend <b>44</b> and bead <b>46</b> of the shaft <b>24</b> are pulled all the way through the plug <b>14</b> until released therefrom, and drawn back into engagement with the plunger <b>30</b>. As the shaft <b>24</b> is moved further proximally relative to the hypotube <b>20</b>, movement of the shaft <b>24</b> causes the guillotine <b>32</b> to slide past the window <b>28</b> and sever the proximal portion of the suture <b>16</b> from the portion of the suture attached to the cinch. Once the suture <b>16</b> is severed, a jerking motion is applied to the applicator <b>10</b> to release the engagement formed by the dimpling structure between to the cinch <b>12</b>, <b>14</b> and applicator <b>10</b>.

p-0010The applicator and cinch are thereby together capable of effectively securing stitched suture to tissue.

SUMMARY OF THE INVENTION

p-0011Notwithstanding the effectiveness of the prior applicators and cinches, several improvements have been made which facilitate endoscopic application of a two-part cinch to suture. In accord with the invention, a system including a two-part suture cinch and cinch applicator is provided. The system has particular use in a NOTES procedure in which an endoscopic stitching instrument has applied one or more stitches of suture through tissue. In a mode of such stitching, a needle fixed to one of the suture is advanced through the tissue and carries the suture through the tissue. Once the tissue is sufficiently stitched to approximate the tissue, the system of the cinch and cinch applicator is provided for cinching the suture against the tissue and/or relative to the suture needle.

p-0012The cinch applicator includes an elongate tubular member, a plunger engaged within the distal end of the tubular member, a flexible shaft extending through the tubular member and plunger, and a proximal handle for moving the shaft longitudinally relative to the tubular member. The tubular member may be a unitary elongate construct or may be comprised of a proximal, longer, flexible, first tubular member and a distal, shorter, rigid, second tubular member, such as a hypotube, longitudinally coupled to the distal end of the first tubular member.

p-0013The tubular member includes a side window and a latch. The plunger includes an upper housing, a structure that engages the collar, a guillotine, a floor below the guillotine, and a base provided with a catch engaged by the latch of the tubular member to retain the position of the plunger within the tubular member. The suture cinch includes a collar and a plug. The collar is provided in the upper housing of the plunger and locked therein by an engagement at the plunger window. The distal end of the shaft extends beyond the distal end of the tubular member in an initial position with the plug coupled to the distal end of the flexible shaft. In operation the collar can be extended over the suture, and the flexible shaft can be withdrawn relative to the tubular member, drawing the plug into a coupled relationship with the collar and thereby clamping a portion of the suture between the plug and collar when the shaft is moved into the applied position. The coupled cinch plug and collar are released from engagement with the applicator and the suture is severed by movement of the guillotine past the side window of the tubular member.

p-0014In one embodiment, the cinch collar includes an elongate tubular body that is received in the housing of the plunger. The collar body includes a shallow partially circumferential rib that is engaged in a snap-fit engagement with structure of the plunger to lock the longitudinal location of the collar. When engaged, the collar body extends proximally beyond the guillotine of the plunger to shield the cutting edge of the guillotine. The collar has a distal outer lip that is received over the distal end of the tubular member and forms a distal taper that permits close approximation to tissue from various angles without damage to the tissue. The proximal end of the collar is stepped to a smaller diameter inner lip.

p-0015The cinch plug includes an elongate tubular body substantially longer in length than the collar. A central portion of the plug body substantially corresponds in length to the length of the collar, and has an outer diameter substantially corresponding to the inner diameter of the collar. A distal end portion of the plug is bulbous and has a larger diameter than the central portion. The plug body gradually increases in dimension from the central portion to define the bulbous distal end portion, which tapers to a distal tip. A proximal end portion gradually tapers away from the central portion to define a circumferential groove that corresponds in location with the step at the proximal end of the cinch collar when the collar and plug are mated are discussed below; the groove is substantially longer than the inner lip. There is no stepwise change in outer diameter along the central and distal portions of the plug; all diametrical changes are gradual. The proximal end tapers to a proximal tip that is provided with a small barb that can engage the proximal inner lip of the collar. A stepped throughbore is provided within the plug with the larger diameter of the throughbore located within the distal end portion. The flexible shaft is straight all the way through the plug body and includes an end with a bead that is retained in the larger diameter portion of the cinch plug throughbore (but too large to readily pass through the smaller diameter portion).

p-0016In operation, a free end of a length of suture attached to tissue must be loaded through the applicator. Such suture includes one end permanently fixed to the needle and located on one side of tissue, and a free end. In one embodiment, the free end of the suture extends through a working channel of an endoscope and out of the user-operated end of the endoscope. Loading the suture into the applicator requires advancing the suture through a pathway defined between the plug and the collar, through the collar and plunger, and out the window of the tubular member to back outside the applicator. The applicator is then advanced over the suture through the working channel of the endoscope to the tissue so that the cinch can be approximated with the tissue.

p-0017A suture threader may be provided to facilitate feeding the free end of suture through the pathway in the applicator. In one embodiment, the suture threader includes a distal guide, an intermediate resilient suture catch, a neck and a proximal handle. In an embodiment, a suture catch is defined by two arms attached at proximal and distal end and having central portions thereof biased away from one another. The threader is inserted through the pathway, in the opposite direction from which the suture must be inserted. That is, the guide is inserted from outside the applicator, through the window in the tubular member, through the collar and out the distal end of the collar. Once properly positioned, the catch is located distal of the collar and in an open position; i.e., with the central portion of the arms biased apart to a dimension larger than capable of passing through the collar, the neck extends within the portion of the pathway inside the applicator, and the handle is provided outside the applicator, preferably adjacent the window. The threader is dimensioned such that the open catch, neck, and handle are fixed in position relative to the applicator until forcibly withdrawn by the user. The applicator is preferably provided with the suture threader extending through the pathway in its as-assembled configuration by a manufacturer.

p-0018The suture is then inserted into the catch of suture threader, with a length of the suture drawn through the opening between the arms. Then the handle of the threader is pulled proximally to withdraw the threader from the pathway through the applicator, thus forcibly retracting the open arms against the collar and causing the arms to move against their bias into a closed position. In doing so, the arms also grasp the suture and draw the suture through the pathway defined by the collar, the plunger, and the window of the tubular member so that the applicator is situated about the suture ready for cinch application.

p-0019In another embodiment, the suture threader includes a proximal end extending out of the endoscope, a thin elongate portion extending alongside the cinch applicator within the working channel of the endoscope, and a distal portion being a U-shaped loop of suture. A portion of the threader is inserted through the pathway in the cinch applicator, with the U-shaped loop of suture extending between the cinch collar and cinch plug. An endoscopic stitching instrument is operated to move a suture attached to tissue through the U-shaped loop. The proximal end of the suture threader is actuated from outside the endoscope to retract the loop and cause the suture to be pulled through the pathway to the load the applicator with suture.

p-0020Once the applicator is loaded with suture, the distal end of the applicator is advanced along the suture until contacted at the location where the suture extends from the tissue. While the applicator is held at that location, tension is manually applied to the suture (from outside the proximal end of the endoscope), and the proximal handle is operated to move the flexible shaft from the initial position toward the applied position. As the shaft is moved proximally relative to the tubular member, the plug is drawn into the collar, capturing the suture between the exterior of the plug and the interior of the collar. The shape of the plug (relative to the prior art plug) prevents the shaft from prematurely detaching from the plug, which would potentially result in a misfire. In addition, the locked engagement between the collar and plunger prevents premature release of the collar from the applicator. As the plug is completely retracted into the collar, the barb at the proximal end portion of the plug engages the internal lip at the proximal end of the collar, thereby locking the plug to the collar with the suture trapped therebetween. Further retraction of the flexible shaft causes the bead at the distal end of the shaft to deform the smaller diameter portion of the throughbore of the plug and pull through the plug to be released from the plug. The bead is retracted against the floor of the plunger. Further force on the flexible shaft in the proximal direction results in (i) the engagement between the latch of the tubular member within the catch of the plunger to permit movement of the plunger within the tubular member, (ii) movement of the plunger relative to the tubular member such that the window of the plunger is retracted from over the rib of the collar, thereby unlocking the collar, freeing the cinch, and allowing the cinch to readily deploy from the applicator without any additional user activation, and (iii) movement of the guillotine into contact with the suture to sever the suture so that the cinched suture is freed from remaining suture extending through the working channel. With the suture cinched against the tissue, the applicator may then be withdrawn from the endoscope.

p-0021The placement of the plunger between the cinch collar and tubular member provides several advantages. First, a barrier is provided between the exterior surface of the collar and any sharp features of the tubular member. Second, the engagement features between the plunger and tubular member (catch and latch) offer precise component alignment. Third, the engagement features between the plunger and cinch collar (window and outer rib) offer precise location of the collar relative to the plunger. Fourth, because the collar extends back to hide the guillotine from the suture prior to disengagement of the latch and catch, the suture is protected from premature cutting. Fifth, the engagement features between the plunger and cinch prevent premature release of the collar until after the cinch has been applied.

p-0022In addition, the tapered and smoothly transitioning plug and tapered collar are easier to advance through the working channel on an endoscope. In addition, the longer plug length relative to the length of the collar provides a greater length over which the suture is captured. This provides enhanced retention strength. Moreover, the forward end of the suture will exit the cinch at the junction between the tapered distal lip of the collar and the transition between the central portion and the distal end portion of the plug. A large length of the cinch is provided to each side of the exit portion of the suture. As a result, the cinch may function as a T-tag, rotating from a longitudinal orientation (parallel to the longitudinal axis of the tubular member) to a transverse orientation to lie against the tissue thus providing a significantly larger contact surface area that provides greater resistance against tissue.

p-0023Additional objects and advantages of the invention will become apparent to those skilled in the art upon reference to the detailed description taken in conjunction with the provided figures.

BRIEF DESCRIPTION OF THE DRAWINGS

p-0024<figref idrefs="DRAWINGS">FIG. 1</figref> is a partial section of a distal end of a prior art cinch applicator and a prior art two-part cinch.

p-0025<figref idrefs="DRAWINGS">FIG. 2</figref> is a partial section of a cinch applicator loaded with a two-part cinch according to an embodiment of the invention.

p-0026<figref idrefs="DRAWINGS">FIG. 3</figref> is an enlarged distal end of view of the inch applicator and two-part cinch shown in <figref idrefs="DRAWINGS">FIG. 2</figref>.

p-0027<figref idrefs="DRAWINGS">FIGS. 4 and 5</figref> are perspective views showing use of a first embodiment of a suture threader to thread suture through a pathway of the cinch applicator according to the invention.

p-0028<figref idrefs="DRAWINGS">FIG. 6</figref> is a longitudinal section view of the cinch applicator in a first position as loaded with suture by the first embodiment of a suture threader.

p-0029<figref idrefs="DRAWINGS">FIG. 7</figref> is a longitudinal section view of the cinch applicator, as loaded with suture by the first embodiment of a suture threader, with the applicator in a second position in which the cinch plug has been drawn into the cinch collar to clamp suture between the plug and collar.

p-0030<figref idrefs="DRAWINGS">FIG. 8</figref> is a longitudinal section view of the cinch applicator, as loaded with suture by the first embodiment of a suture threader, with the applicator in a third position in which the distal end of the shaft has been drawn through the cinch plug and against the floor of the plunger.

p-0031<figref idrefs="DRAWINGS">FIG. 9</figref> is a longitudinal section view of the cinch applicator, as loaded with suture by the first embodiment of a suture threader, with the applicator in a fourth position in which the plunger has been retracted relative to the rigid, second tubular member of the cinch applicator.

p-0032<figref idrefs="DRAWINGS">FIG. 10</figref> is a longitudinal section view of the cinch applicator, as loaded with suture by the first embodiment of a suture threader, with the applicator in a fifth position in which the plunger has been retracted to sever the suture and release the cinch.

p-0033<figref idrefs="DRAWINGS">FIG. 11</figref> is a perspective partial section view of tissue with a cinched suture on one side of the tissue and a needle on the other side of the tissue.

p-0034<figref idrefs="DRAWINGS">FIGS. 12 and 13</figref> illustrate use of a second embodiment of a suture threader in conjunction with an endoscope and endoscope suture stitching device to thread suture through a pathway of the cinch applicator according to the invention.

p-0035<figref idrefs="DRAWINGS">FIG. 14</figref> is a longitudinal section view of the cinch applicator in a first position being loaded with suture by the second embodiment of the suture threader.

p-0036<figref idrefs="DRAWINGS">FIG. 15</figref> is a longitudinal section view of the cinch applicator, as loaded with suture by the second embodiment of a suture threader, with the applicator in a second position in which the cinch plug has been drawn into the cinch collar to clamp suture between the plug and collar.

p-0037<figref idrefs="DRAWINGS">FIG. 16</figref> is a longitudinal section view of the cinch applicator, as loaded with suture by the second embodiment of a suture threader, with the applicator in a third position in which the distal end of the shaft has been drawn through the cinch plug and against the floor of the plunger.

p-0038<figref idrefs="DRAWINGS">FIG. 17</figref> is a longitudinal section view of the cinch applicator, as loaded with suture by the second embodiment of a suture threader, with the applicator in a fourth position in which the plunger has been retracted relative to the rigid, second tubular member of the cinch applicator.

p-0039<figref idrefs="DRAWINGS">FIG. 18</figref> is a longitudinal section view of the cinch applicator, as loaded with suture by the second embodiment of a suture threader, with the applicator in a fifth position in which the plunger has been retracted to sever the suture and release the cinch.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

p-0040A cinch applicator and two-part cinch are provided. The system has particular use in a NOTES procedure in which an endoscopic stitching instrument has applied one or more stitches of suture through tissue. However, it is appreciated that the system may have uses in other procedures, particularly other endoscopic procedures. The applicator and cinch may have uses in both open and closed surgical procedures, be used on humans as well as with other mammals, and may be used in procedures on living individuals as well as cadaverous bodies. The terms ‘proximal’ and ‘distal’ have their conventional meaning, with ‘proximal’ referring to a location relatively closer to a user-held and user-operated end of the cinch applicator, and ‘distal’ referring to a location relatively further from the user-held and user-operated end.

p-0041Referring now to <figref idrefs="DRAWINGS">FIG. 2</figref>, an embodiment of the cinch applicator <b>100</b> according to the invention includes an elongate, flexible, first tubular member <b>102</b>, a shorter, rigid, second tubular member <b>104</b> fixed to the distal end of the flexible tubular member <b>102</b>, a plunger <b>106</b> engaged within the second tubular member <b>104</b>, a flexible shaft <b>108</b> extending through the flexible and rigid tubular members <b>102</b>, <b>104</b> and plunger <b>106</b>, and a proximal handle <b>110</b> for moving the flexible shaft <b>108</b> longitudinally relative to the tubular members <b>102</b>, <b>104</b>. The proximal handle <b>110</b> may include a stationary shaft <b>110</b><i>a </i>and movable slide or spool <b>110</b><i>b </i>conventionally used in association with many endoscopic instruments. Alternatively, the handle <b>110</b> may include a lever rotatable relative to a stationary member, or a movable trigger, or any other suitable handle assembly for longitudinally displacing the flexible shaft <b>108</b> relative to the first and second tubular members <b>102</b>, <b>104</b>. The flexible tubular member <b>102</b> may be made extruded from a polymer or be formed of a helically wound metal or polymer defining a structural coil, preferably provided with a lubricious sheath to facilitate its passage through a working channel of an endoscope. The rigid second tubular member <b>104</b> is preferably a section of a hypotube, although other constructs may be used, and may be crimped, bonded or otherwise attached at the distal end of the flexible first tubular member <b>102</b>. The plunger <b>106</b> is preferably molded from plastic. The flexible shaft <b>108</b> is preferably a wire, cable, or other metal or polymeric filamentary structure capable of being subject to the tensile forces necessary to function in accord with the invention described below. That is, the shaft preferably is substantially inelastic and will not be deformed in elongation under the applied tensile forces. The flexible tubular member <b>102</b> and flexible shaft <b>108</b> have sufficient flexibility to be passed through a curvilinear working channel of an endoscope; even an endoscope that is retroflexed.

p-0042More particularly, the rigid second tubular member <b>104</b> preferably has a sufficiently short length that permits its passage through the non-linear working channel of an endoscope. By way of example, the length of the rigid tubular member <b>104</b> is preferably 12 mm. The rigid tubular member <b>104</b> includes a side window <b>112</b> and a latch <b>114</b>. The latch <b>114</b> is preferably a leaf spring defined by a cut through a portion of the side wall of the rigid tubular member <b>104</b>, the leaf spring extending into the interior of the tubular member and capable of being moved radially outward.

p-0043The plunger <b>106</b> includes an upper housing <b>116</b>, a partially circumferential distal side opening <b>118</b>, a guillotine <b>120</b> distally bordering a central opening <b>122</b> coinciding with the side window <b>112</b> of the rigid tubular member <b>104</b>, a preferably sloped floor <b>124</b> proximally bordering the opening <b>122</b>, and a base <b>126</b> provided with a catch <b>128</b>. The catch <b>128</b> may comprise a groove, and is engaged by the latch <b>114</b> to retain the longitudinal position of the plunger <b>106</b> within the second tubular member <b>104</b>. The latch <b>114</b> and catch <b>128</b> are respectively positioned to locate the plunger <b>106</b> within and relative to the second tubular member <b>104</b> at a specific location (and a reproducible location across the manufacture of many cinch applicators).

p-0044Turning now to <figref idrefs="DRAWINGS">FIG. 3</figref>, the suture cinch includes two components—a collar <b>132</b> and a plug <b>134</b>. Each of the collar <b>132</b> and plug <b>134</b> are preferably molded or machined from a biocompatible polymer. The collar <b>132</b> is provided in the upper housing <b>116</b> of the plunger <b>106</b> and is locked therein by an engagement between the collar and the plunger, described more particularly below. The distal end of the shaft <b>108</b> extends, in a first position, beyond the distal end <b>136</b> of the second tubular member <b>104</b>, with the plug <b>134</b> coupled to the distal end of the flexible shaft <b>108</b>.

p-0045More particularly, the cinch collar <b>132</b> includes an elongate tubular body <b>140</b> that is received in the housing <b>116</b> of the plunger <b>106</b>. The collar body <b>140</b> is preferably approximately 4 mm in length. The body <b>140</b> includes a shallow partially circumferential rib <b>142</b> that is engaged in a snap-fit engagement into the side opening <b>118</b> of the plunger <b>106</b> to lock the collar to the plunger and relative to the second tubular member. When engaged, the collar body <b>140</b> extends proximally to shield the sharp edge of the guillotine <b>120</b> of the plunger <b>106</b> between the collar <b>132</b> and the second tubular member <b>104</b>. The collar <b>132</b> has a distal lip <b>144</b> that is received over the distal end of the second tubular member <b>104</b> and forms a distal taper that permits close approximation to tissue from various angles without damage to the tissue. The proximal end of the collar <b>132</b> is stepped to a smaller diameter inner lip <b>148</b>.

p-0046The cinch plug <b>134</b> includes an elongate tubular body <b>150</b> substantially longer in length than the collar <b>132</b>. By way of example, the cinch plug <b>134</b> is preferably approximately 8 mm in length that, in view of how the cinch collar <b>132</b> and plug <b>134</b> are assembled as discussed below, is also the total cinch length. A central portion <b>152</b> of the plug body <b>150</b> substantially corresponds in length to the length of the collar <b>132</b>, and has an outer diameter substantially corresponding to the inner diameter of the collar. A distal end portion <b>154</b> of the plug <b>134</b> is bulbous and has a larger diameter than the central portion <b>152</b>. The body <b>150</b> gradually increases in dimension from the central portion <b>152</b> to define the bulbous distal end portion <b>154</b>, which tapers to a distal tip <b>156</b>. A proximal end portion <b>158</b> gradually tapers away from the central portion <b>152</b> to define a circumferential groove <b>160</b> that corresponds in location with the lip <b>148</b> at the proximal end of the cinch collar <b>132</b> when the collar and plug are mated are discussed below; the groove <b>160</b> is substantially longer than the step. There is no stepwise change in outer diameter along the central and distal portions <b>152</b>, <b>154</b> of the plug. The proximal end portion <b>158</b> tapers to a proximal tip <b>162</b> which functions as a small barb that can engage the proximal inner lip <b>148</b> of the collar <b>132</b>. A stepped throughbore <b>164</b> is provided through the plug <b>134</b>, with the larger diameter portion <b>164</b><i>a </i>of the throughbore located within the distal end portion <b>154</b>. The flexible shaft <b>108</b> is straight all the way through the plug body <b>134</b> and includes an end with a bead <b>166</b> that is provided in the larger diameter portion <b>164</b><i>a </i>of the throughbore <b>164</b> (but too large to readily pass through a smaller diameter portion <b>164</b><i>b</i>).

p-0047The cinch applicator may be provided with a suture threader to assist in feeding a free end of a length of suture stitched to tissue into the applicator. One embodiment of a suture threader <b>170</b> for manually feeding the free end <b>172</b> of a length of suture <b>174</b> stitched to tissue into the applicator <b>100</b> is shown in <figref idrefs="DRAWINGS">FIG. 4</figref>. Suture threader is ideally suited for threading a length of suture extending from the stitch, through a working channel of an endoscope and outside the patient suture, and then into the applicator. It is recognized that, according to a preferred use for the applicator and cinch, the opposite end of <b>175</b> the suture <b>174</b> is fixed to a needle <b>188</b> located on an opposite side of tissue <b>180</b> (See <figref idrefs="DRAWINGS">FIG. 11</figref>, discussed in more detail below). In one embodiment, the free end of the suture extends from the tissue and through the working channel to the user-operated end of an endoscope. Loading the free end <b>172</b> of suture into the cinch applicator <b>100</b> requires advancing the suture through a pathway defined between the collar <b>132</b> and plug <b>134</b>, through the collar <b>132</b>, and out through the window <b>112</b> of the rigid tubular member <b>104</b> to back outside the applicator. The applicator <b>110</b> is then advanced over the suture <b>174</b> through the working channel to the tissue so that the two-part cinch <b>130</b> can be approximated with the tissue.

p-0048The suture threader <b>170</b> includes a distal guide <b>176</b>, an intermediate resilient suture catch <b>178</b>, a neck <b>180</b>, and a proximal handle <b>182</b>. More specifically, the suture catch <b>178</b> is defined by two arms <b>178</b><i>a</i>, <b>178</b><i>b </i>attached at proximal and distal ends and having central portions thereof biased away from one another to form an eye therebetween that has a dimension larger than capable of passing through the collar <b>132</b>. The arms are collapsed against their bias and forced through the pathway from a direction opposite from which the suture <b>174</b> is to be inserted. That is, the guide <b>176</b> is inserted from outside the applicator, through the window <b>112</b> of the second tubular member <b>102</b>, and through the collar <b>132</b> and out the distal end of the collar. Once properly positioned, the suture catch <b>178</b> is located distal of the collar <b>132</b> and in an open position. The threader handle <b>182</b> is retained outside the applicator, preferably adjacent the window <b>112</b>. The threader is dimensioned such that the handle <b>182</b> and open suture catch <b>178</b> are fixed in position relative to the applicator until forcibly withdrawn by the user. The applicator <b>100</b> is preferably provided with the suture threader <b>170</b> in position, in the as-manufactured condition as prepared for use by the user.

p-0049The free end <b>172</b> of the suture <b>174</b> is then thread into the eye defined by the open arms <b>178</b><i>a</i>, <b>178</b><i>b </i>of the installed suture catch <b>178</b>. Referring to <figref idrefs="DRAWINGS">FIG. 5</figref>, then the threader handle <b>182</b> is pulled proximally to withdraw the threader <b>170</b> from the applicator <b>100</b>, thus forcibly moving the arms <b>178</b><i>a</i>, <b>178</b><i>b </i>against their bias into a closed position, as retracted against the collar <b>132</b>. Referring to <figref idrefs="DRAWINGS">FIGS. 5 and 6</figref>, the closed arms <b>178</b><i>a</i>, <b>178</b><i>b </i>grasp the free end <b>172</b> of suture <b>174</b> and draw the suture through the pathway defined through the collar <b>132</b>, the plunger <b>106</b>, and out of the window <b>112</b> of the second tubular member <b>104</b> so that the suture is thread through the applicator <b>100</b> for cinch application.

p-0050Once the suture <b>174</b> is thread through the described pathway of the cinch collar and cinch applicator (<figref idrefs="DRAWINGS">FIG. 6</figref>), the distal end of the cinch applicator is advanced over the suture <b>174</b>. The suture <b>174</b> is pulled taut, and the distal end of the applicator is advanced along the suture until contacted against the location where the suture enters the tissue. While the applicator is held at that location, tension is manually applied to the suture (from outside the proximal end of the endoscope). Referring to <figref idrefs="DRAWINGS">FIG. 7</figref>, the proximal handle <b>110</b> of the applicator (<figref idrefs="DRAWINGS">FIG. 2</figref>) is then operated to move the flexible shaft <b>108</b> from the initial first position toward an applied position. As the shaft <b>108</b> is moved proximally relative to the second tubular member <b>104</b>, the plug <b>134</b> is drawn into the collar <b>132</b>, capturing the suture <b>174</b> between the exterior of the plug and the interior of the collar. The rounded bulbous shape of the plug <b>134</b> prevents the plug from inadvertently catching on tissue or another instrument that could cause premature detachment of the flexible shaft <b>108</b> from the plug <b>134</b>, and potentially result in a misfire. Specifically, testing has shown that the reduced dimension and rounded shape of the distal end portion <b>154</b> of the plug (without a stepped expansion to a large flattened flange) significantly reduce misfiring associated with contact of the plug against approximated tissue relative to the prior art cinch. In addition, the locked engagement between the collar <b>132</b> and plunger <b>106</b> prevents premature release of the collar from the applicator. As the plug <b>134</b> is completely refracted into the collar <b>132</b>, the barb <b>162</b> at the proximal end portion of the plug is captured by the internal step <b>148</b> at the proximal end of the collar <b>132</b>, with the internal step seating in the groove <b>160</b>, thereby locking the plug <b>132</b> to the collar <b>134</b> with the suture <b>174</b> trapped therebetween.

p-0051Referring to <figref idrefs="DRAWINGS">FIG. 8</figref>, further retraction of the flexible shaft <b>108</b> relative to the rigid tubular member <b>104</b> causes the bead <b>166</b> at the distal end of the shaft to slightly deform the smaller diameter portion <b>164</b><i>b </i>of the throughbore of the plug <b>134</b>, and pull through the plug to be freed from the plug. The bead <b>166</b> is retracted against the floor <b>124</b> of the plunger <b>106</b>.

p-0052Turning to <figref idrefs="DRAWINGS">FIGS. 9 and 10</figref>, further sufficient force on the flexible shaft <b>108</b> in the proximal direction results in (i) disengagement of the catch <b>128</b> of the plunger <b>106</b> from the latch <b>114</b> of the second tubular member <b>104</b> to permit movement of the plunger within the second tubular member, (ii) movement of the plunger <b>106</b> relative to the second tubular member <b>104</b> such that the window <b>118</b> of the plunger is retracted from over the rib <b>142</b> of the collar <b>132</b>, thereby unlocking the collar <b>132</b> and freeing the engaged two-part cinch from the applicator, and readying the cinch to deploy from the applicator <b>100</b> without any additional user activation, and (iii) movement of the guillotine <b>120</b> into an exposed position into contact with the suture <b>174</b> to sever the suture so that the cinch is freed from remaining suture extending through the working channel. With the suture cinched against the tissue, the applicator <b>100</b> may then be withdrawn from the endoscope.

p-0053The use of the plunger <b>106</b> between the cinch collar <b>132</b> and second tubular member <b>104</b> provides several advantages. First, a barrier is provided between the exterior surface of the collar <b>134</b> and the sharp metal features of a metal hypotube (when such a structure is utilized for the second tubular member). Second, the engagement features between the second tubular member <b>104</b> and plunger <b>106</b> (latch <b>114</b> and catch <b>128</b>) offers precise component alignment. Third, the engagement features between the plunger <b>106</b> and cinch collar <b>132</b> offer precise location of the collar relative to the plunger. This is important, as the collar can be precisely positioned to extend back to hide the guillotine <b>120</b> from the suture <b>174</b> prior to intentional cutting, thereby protecting the suture from premature cutting. Fourth, the engagement features between the plunger <b>106</b> and cinch collar <b>132</b> prevent premature release of the cinch (or just) collar until after the cinch has been intentionally applied.

p-0054It is appreciated that the taper-transitioning plug <b>134</b> and tapered collar <b>132</b> are easier to advance through the working channel on an endoscope; i.e., the shapes of such components specifically overcome prior art issues with respect to feeding the structure of components through a working channel. In addition, the longer length of the plug <b>134</b> relative to the length of the collar <b>132</b> provides a greater length over which the suture is captured. This provides enhanced retention strength. Moreover, referring back to <figref idrefs="DRAWINGS">FIG. 10</figref>, the forward end of the cinched suture will exit the cinch at the junction between the tapered distal lip <b>144</b> of the collar <b>132</b> and the transition between the central portion <b>152</b> and the distal end portion <b>154</b> of the plug <b>134</b>. A large length of the cinch <b>130</b> is provided to each side of the exiting suture. Referring to <figref idrefs="DRAWINGS">FIG. 11</figref>, as a result, the coupled cinch <b>130</b> may function as a T-tag, rotating from a longitudinal orientation (parallel to the longitudinal axis of the second tubular member) to a transverse orientation to lie against the tissue <b>186</b>, thus providing a significantly larger contact surface area that provides greater resistance against tissue and thereby prevent pull-through. <figref idrefs="DRAWINGS">FIG. 11</figref> also show a needle <b>188</b> attached to the suture on the side of tissue opposite the cinch <b>130</b>.

p-0055It is also appreciated that the suture can be thread through the pathway while the applicator is in situ, i.e., with the applicator extended through the working channel of the endoscope and the applicator located adjacent the stitch. Turning now to <figref idrefs="DRAWINGS">FIG. 12</figref>, an endoscopic stitching instrument <b>200</b> is shown mounted at the distal end of an endoscope <b>202</b>. The endoscope includes a first working channel <b>204</b> through which a needle catch device <b>206</b> extends and a second working channel <b>208</b> through which the cinch applicator <b>100</b> extends. The stitching instrument <b>200</b> includes an arm <b>210</b> that rotates a releasable needle <b>212</b> in an arc through captured tissue <b>214</b> and into engagement with the needle catch device <b>206</b> (the needle shown released from the arm and engaged in the catch device). A first portion <b>174</b><i>a </i>of the suture extends within the first working channel <b>204</b> along the outside of the catch device <b>206</b>, and a second portion <b>174</b><i>b </i>of the suture extends between the tissue <b>214</b> and the needle <b>212</b>. The needle <b>212</b> can be selectively engaged to the needle catch device <b>206</b> and released from the arm <b>210</b> for repositioning of the arm relative to the needle <b>212</b> and tissue <b>214</b> to advance a stitch of suture <b>174</b>. Use of the endoscopic stitching instrument <b>200</b> is described in more detail in co-owned US Pub. No. 20090312775A1. Once the desired stitch is complete, the cinch applicator <b>100</b> is advanced through the second working channel <b>208</b>.

p-0056The cinch applicator <b>100</b> is provided with another embodiment of a suture threader <b>270</b>. The suture threader <b>270</b> includes a distal loop <b>278</b>, a central portion <b>280</b> and a proximal end <b>282</b>. The distal loop <b>278</b> has an opening of sufficient size to receive the needle <b>212</b> and as well the second portion <b>174</b><i>b </i>of the needle suture <b>174</b> therethrough (with the first portion <b>174</b><i>a </i>residing outside the loop <b>278</b>). When the cinch applicator <b>100</b> is fully advanced into the working channel <b>208</b>, the loop <b>278</b> is naturally positioned to receive the needle <b>212</b> within the loop <b>278</b> as the arm <b>210</b> is rotated to advance the needle into the needle catch device <b>206</b>. The distal loop <b>278</b> is also sufficiently small to be able to be drawn back through the pathway (defined through the collar <b>132</b>, the plunger <b>106</b>, and the window <b>112</b> of the second tubular member <b>104</b> (see <figref idrefs="DRAWINGS">FIG. 14</figref>)) in conjunction with the second portion <b>174</b><i>b </i>of the needle suture <b>174</b>. The distal end <b>278</b> may comprises a structure other than a loop, such as J-shaped construct or another suitable shape for receiving and retaining the second portion <b>174</b><i>b </i>of the needle suture as it is pulled back through the pathway, and may be made from a material other than suture. The central portion <b>280</b> of the threader <b>270</b> is preferably a elongate flexible element, preferably a strand of suture, extending from the loop <b>278</b>. At least one of the distal and central portions <b>278</b>, <b>280</b> extends through the pathway defined through the collar <b>132</b>, the plunger <b>106</b>, and out of the window <b>112</b> of the second tubular member <b>104</b>, with the central portion <b>280</b> extending alongside the full length of the applicator <b>100</b>, while the applicator is inserted within the working channel <b>208</b> of the endoscope (i.e., in a position with the cinch plug <b>134</b> extending out of the distal end of the endoscope <b>202</b>, and the cinch collar <b>132</b> located even with or distal the distal face <b>202</b><i>a </i>of the endoscope). The proximal end of the suture threader <b>282</b> extends out of the proximal end of the second working channel <b>208</b> and is accessible to a user of the endoscope to permit manual retraction of the suture threader <b>270</b> relative to the cinch collar <b>132</b>. The proximal end <b>282</b> may include a further extension of the suture comprising the central portion <b>280</b>, or may be in the form of a finger loop (as shown), a dedicated handle, or some integration into the handle <b>110</b> (<figref idrefs="DRAWINGS">FIG. 2</figref>) that operates movement of the cinch plug <b>134</b> relative to the cinch collar <b>132</b>. Once the stitching instrument <b>200</b> has been operated to move the needle <b>212</b> through the loop <b>278</b> at the distal end of the threader, a consequence is that the second portion <b>174</b><i>b </i>of the suture has also been thread through the loop <b>278</b> (with the portion <b>174</b><i>a </i>located outside the loop).

p-0057Referring to <figref idrefs="DRAWINGS">FIGS. 13 and 14</figref>, once the second portion <b>174</b><i>b </i>of the suture is situated within the loop <b>278</b>, the proximal end <b>282</b> of the suture threader <b>270</b> is manipulated to retract the loop <b>278</b> and pull a captured portion of the distal portion <b>174</b><i>a </i>of the suture toward the collar <b>132</b>. As the suture portion <b>174</b><i>b </i>is pulled in this manner (noting that the suture portion <b>174</b><i>b </i>is coupled to both the tissue <b>214</b> and the needle), the retracted suture portion <b>174</b><i>b </i>is doubled-over (at <b>174</b><i>c</i>) and pulled into and through the pathway (<b>132</b>, <b>106</b>, <b>112</b>) and out of the side window <b>112</b> in this doubled-over configuration. The distal loop <b>278</b> may be self-closing as it is pulled (like a noose) to assist in retaining a grip on the suture portion <b>174</b><i>b </i>as its is pulled through the pathway (and later cut as described hereinafter). The suture threader is retracted until the suture is drawn through the side window <b>112</b>. At this point, the distal end loop <b>278</b> of the suture threader resides outside the applicator <b>100</b> and within the second working channel <b>208</b>.

p-0058With the suture portion <b>174</b><i>b </i>thread through the pathway of the applicator <b>100</b>, the applicator is operated as described above to secure the cinch onto the suture. Briefly, with reference to <figref idrefs="DRAWINGS">FIG. 15</figref>, the distal end of the collar <b>132</b> is advanced to the tissue <b>214</b>, and cinch wire <b>108</b> is moved relative to the hypotube <b>104</b> to cause the collar <b>132</b> to draw the plug <b>134</b> into the collar <b>132</b>, thereby capturing the doubled-over portion <b>274</b><i>c </i>of suture between the plug and collar. It is appreciated that the collar <b>132</b> and plug <b>134</b> are appropriately dimensioned and of a material that accommodates the thickness of the doubled-over suture portion <b>274</b><i>c</i>. Then, referring to <figref idrefs="DRAWINGS">FIG. 16</figref>, the cinch wire <b>108</b> is retracted relative to the plug <b>134</b> to release the bead <b>166</b> at the distal end of the wire from the plug <b>134</b> and draw the bead <b>166</b> against the floor <b>124</b> of the plunger <b>106</b>. Referring to <figref idrefs="DRAWINGS">FIG. 17</figref>, as the plunger <b>106</b> is fully retracted, the cinch <b>130</b> is released from mechanical engagement with the applicator <b>100</b>. In addition, the guillotine <b>120</b> of the plunger <b>106</b> begins to move across the window <b>112</b>. Further retraction of the plunger <b>106</b>, as shown in <figref idrefs="DRAWINGS">FIG. 18</figref>, causes the guillotine <b>120</b> to be drawn across the doubled-over suture <b>174</b><i>c </i>and sever it, leaving a remaining portion <b>174</b><i>d </i>coupled to the loop <b>278</b> of the suture threader <b>270</b>. Once the suture is severed, the suture threader <b>270</b> may be withdrawn from the endoscope working channel. The applied cinch <b>130</b> has the same advantages described above.

p-0059There have been described and illustrated herein embodiments of a cinch applicator and a method of applying a cinch. While particular embodiments of the invention have been described, it is not intended that the invention be limited thereto, as it is intended that the invention be as broad in scope as the art will allow and that the specification be read likewise. Thus, while particular dimensions have been described for portions of the cinch applicator, it will be appreciated that other suitable dimensions for components can be used as well. In addition, while preferred dimensions are presented for the two-part cinch, it is appreciated that the collar and plug may be provided in different dimensions as well. Also, while preferred materials are described, it is appreciated that other materials can be used. It will therefore be appreciated by those skilled in the art that yet other modifications could be made to the provided invention without deviating from its scope as claimed.